experimental nested fields enhanced attributes mappings handling feature

app/assets/javascripts/para/inputs/multi-select-input.coffee

@@ -75,8 +75,8 @@ class Para.MultiSelectInput extends Vertebra.View
     else
       @showEmptyListHint(@noSelectedItemsTemplate, @$selectedItems)
 
-  showEmptyListHint: (template, appendTo) ->
-    $(template).appendTo(appendTo)
+  showEmptyListHint: (template, $container) ->
+    $(template).appendTo($container)
 
   onItemRemoved: (selectedItem) =>
     itemIndex = index for item, index in @selectedItems when item.id is selectedItem.id
@@ -155,5 +155,5 @@ class Para.MultiSelectSelectedItem extends Vertebra.View
     @trigger('remove', this)
 
 
-$.simpleForm.onDomReady ->
-  $('[data-multi-select-input]').each (i, el) -> new Para.MultiSelectInput(el: el)
+$.simpleForm.onDomReady ($document) ->
+  $document.find('[data-multi-select-input]').each (i, el) -> new Para.MultiSelectInput(el: el)

app/assets/javascripts/para/inputs/nested_many.coffee

@@ -47,5 +47,5 @@ class Para.NestedManyField
     $target.find('input, textarea, select').eq('0').focus()
 
 
-$.simpleForm.onDomReady ->
-  $('.nested-many-field').each (i, el) -> new Para.NestedManyField($(el))
+$.simpleForm.onDomReady ($document) ->
+  $document.find('.nested-many-field').each (i, el) -> new Para.NestedManyField($(el))

app/controllers/para/admin/base_controller.rb

@@ -27,6 +27,13 @@ def current_ability
 
       private
 
+      # Override cancan controlelr resource class to avoid attributes
+      # assignation issues with resources
+      #
+      def self.cancan_resource_class
+        Para::ControllerResource
+      end
+
       def authorize_admin_access
         authorize! :access, :admin
       end

app/controllers/para/admin/resources_controller.rb

@@ -4,6 +4,7 @@ module Para
   module Admin
     class ResourcesController < Para::Admin::BaseController
       include Para::ModelHelper
+      include Para::AttributesMappingsHelper
 
       class_attribute :resource_name, :resource_class
       load_and_authorize_component
@@ -117,7 +118,7 @@ def resource_params
       end
 
       def parse_resource_params(hash)
-        model_field_mappings(resource_model).fields.each do |field|
+        model_field_mappings(resource_model, mappings: attributes_mappings_for(hash)).fields.each do |field|
           field.parse_input(hash, resource)
         end
 

app/helpers/para/form_helper.rb

@@ -26,6 +26,8 @@ def para_form_for(resource, options = {}, &block)
           if @component.subclassable? && resource.new_record?
             content << form.hidden_field(:type, value: resource.type)
           end
+
+          content << form.attributes_mappings_field
         end
       end
     end

app/helpers/para/model_helper.rb

@@ -5,11 +5,21 @@ def attribute_field_mappings_for(component, relation)
       model_field_mappings(model).fields
     end
 
-    def model_field_mappings(model, attributes = nil)
+    # Second argument can be the whitelist_attributes array or keyword
+    # arguments. This is to ensure backwards compatibility with old plugins.
+    #
+    def model_field_mappings(model, options = {})
+      if Array == options
+        whitelist_attributes = options
+      else
+        whitelist_attributes = options.fetch(:whitelist_attributes, nil)
+        mappings = options.fetch(:mappings, {})
+      end
+
       store_key = ['model', 'mappings', model.name.underscore].join(':')
 
       Para.store[store_key] ||= Para::AttributeFieldMappings.new(
-        model, whitelist_attributes: attributes
+        model, whitelist_attributes: whitelist_attributes, mappings: mappings
       )
     end
 

app/models/para/page.rb

@@ -0,0 +1,5 @@
+module Para::Page
+  def self.table_name_prefix
+    'para_page_'
+  end
+end

app/models/para/page/section.rb

@@ -10,6 +10,47 @@ class Section < ActiveRecord::Base
       def css_class
         @css_class ||= self.class.name.demodulize.underscore.gsub(/_/, '-')
       end
+
+      class << self
+        # This method is a shortcut to create a has_many through relation
+        def section_resources(*args, &block)
+          _ensure_section_resources_relation
+          _create_section_resource_relation_for(*args, &block)
+        end
+
+        private
+
+        def _ensure_section_resources_relation
+          return if @section_resources_already_initialized
+
+          has_many :section_resources, foreign_key: 'section_id',
+                                       class_name: '::Para::Page::SectionResource',
+                                       dependent: :destroy
+          accepts_nested_attributes_for :section_resources, allow_destroy: true
+
+          @section_resources_already_initialized = true
+        end
+
+        def _create_section_resource_relation_for(*args, &block)
+          options = args.extract_options!
+
+          # Allow using :class_name option instead of :source_type to feel more
+          # like a direct has_many relation macro, and try to deduce the target
+          # class name from the relation name.
+          target_class_name = options.fetch(:class_name) do
+            args.first.to_s.singularize.camelize
+          end
+
+          # Fill the through relation options but let the user override them
+          options.reverse_merge!(
+            through: :section_resources,
+            source: :resource,
+            source_type: target_class_name
+          )
+
+          has_many(*args, options, &block)
+        end
+      end
     end
   end
 end

app/models/para/page/section_resource.rb

@@ -0,0 +1,12 @@
+module Para
+  module Page
+    class SectionResource < ActiveRecord::Base
+      self.table_name = 'para_page_section_resources'
+
+      acts_as_orderable
+
+      belongs_to :section
+      belongs_to :resource, polymorphic: true
+    end
+  end
+end

app/views/para/inputs/nested_many/_add.html.haml

@@ -1,2 +1,2 @@
-= link_to_add_association form, attribute_name, partial: find_partial_for(model, 'nested_many/container', partial_dir: 'inputs'), form_name: 'form', class: 'btn btn-primary btn-shadow', data: { :'association-insertion-node' => "##{ dom_identifier }", :'association-insertion-method' => 'append' }, render_options: { nested_attribute_name: attribute_name, orderable: orderable, locals: { model: model, nested_locals: nested_locals, inset: inset } } do
+= link_to_add_association form, attribute_name, partial: find_partial_for(model, 'nested_many/container', partial_dir: 'inputs'), form_name: 'form', class: 'btn btn-primary btn-shadow add-button nested-many-inset-add-button', data: { :'association-insertion-node' => "##{ dom_identifier }", :'association-insertion-method' => 'append' }, render_options: { nested_attribute_name: attribute_name, orderable: orderable, locals: { model: model, nested_locals: nested_locals, inset: inset } } do
     = t('para.form.nested.add')

app/views/para/inputs/nested_many/_add_with_subclasses.html.haml

@@ -1,4 +1,4 @@
-.add-button.dropdown
+.add-button.nested-many-inset-add-button.dropdown
   %button.btn.btn-primary.btn-shadow.dropdown-toggle{ type: 'button', data: { toggle: 'dropdown' } }
     = t('para.form.nested.add')
     %i.fa.fa-angle-down

app/views/para/inputs/nested_many/_container.html.haml

@@ -1,6 +1,6 @@
 - nested_locals ||= {}
 
-.panel.panel-default.form-fields
+.panel.panel-default.form-fields{ class: ('nested-many-inset-panel' if inset) }
   .panel-heading
     = form.reorder_anchor
 

db/migrate/20170324125547_create_para_page_section_resources.rb

@@ -0,0 +1,15 @@
+class CreateParaPageSectionResources < ActiveRecord::Migration
+  def change
+    create_table :para_page_section_resources do |t|
+      t.references :section
+      t.references :resource, polymorphic: true, index: false
+      t.integer :position, default: 0
+      t.jsonb :data
+
+      t.timestamps
+    end
+
+    add_index :para_page_section_resources, [:resource_type, :resource_id], name: :index_para_section_resources_on_resource_type_and_id
+    add_foreign_key :para_page_section_resources, :para_page_sections, column: 'section_id'
+  end
+end

lib/generators/para/page/section/section_generator.rb

@@ -5,15 +5,26 @@ class SectionGenerator < Rails::Generators::NamedBase
 
       source_root File.expand_path("../templates", __FILE__)
 
-      argument :attributes, type: :array
+      argument :attributes, type: :array, required: false, default: []
 
-      def generate_form
+      def generate_model
         template(
           "section.rb.erb",
           "app/models/page_section/#{ singular_namespaced_path }.rb"
         )
       end
 
+      def generate_fields
+        generate 'para:nested_fields', "page_section/#{ singular_namespaced_path }"
+      end
+
+      def generate_template
+        template(
+          "section.html.haml.erb",
+          "app/views/page_section/#{ plural_namespaced_path }/_#{ singular_namespaced_path }.html.haml"
+        )
+      end
+
       private
 
       def attributes_separated_with_commas

lib/generators/para/page/section/templates/section.html.haml.erb

@@ -0,0 +1,3 @@
+<%- attributes.each do |attribute| -%>
+= <%= singular_namespaced_path %>.<%= attribute.name %>
+<%- end -%>

lib/para.rb

@@ -40,6 +40,7 @@
 require 'para/plugins'
 require 'para/config'
 require 'para/model_field_parsers'
+require 'para/attributes_mappings_helper'
 require 'para/attribute_field'
 require 'para/attribute_field_mappings'
 require 'para/inputs'
@@ -62,6 +63,7 @@ module Para
   eager_autoload do
     autoload :Config
     autoload :Component
+    autoload :ControllerResource
     autoload :Generators
     autoload :SimpleFormConfig
     autoload :Routing

lib/para/attribute_field/has_many.rb

@@ -44,17 +44,22 @@ def assign_multi_select_field(params, resource)
         end
       end
 
-      def assign_ordered_through_reflection_ids(reflection, resource, ids)
-        association = resource.association(reflection.name)
+      def assign_ordered_through_reflection_ids(through_reflection, resource, ids)
+        association = resource.association(through_reflection.name)
         join_resources = association.load_target
 
         return association.replace([]) if ids.empty?
 
         new_resources = ids.each_with_index.map do |id, position|
-          join_resource = join_resources.find { |res| res.send(through_relation_source_foreign_key) == id }
+          join_resource = join_resources.find do |res|
+            res.send(through_relation_source_foreign_key) == id &&
+              (!polymorphic_through_reflection? || res.send(reflection.foreign_type) == reflection.klass.name)
+          end
 
           unless join_resource
-            join_resource = association.build(through_relation_source_foreign_key => id)
+            attributes = { through_relation_source_foreign_key => id }
+            attributes[reflection.foreign_type] = reflection.klass.name if polymorphic_through_reflection?
+            join_resource = association.build(attributes)
           end
 
           join_resource.position = position

lib/para/attribute_field/nested_many.rb

@@ -1,13 +1,19 @@
 module Para
   module AttributeField
     class NestedManyField < AttributeField::HasManyField
+      include Para::AttributesMappingsHelper
+
       register :nested_many, self
 
       def parse_input(params, resource)
         if (nested_attributes = params[nested_attributes_key])
           nested_attributes.each do |index, attributes|
-            nested_model_mappings.fields.each do |field|
-              field.parse_input(attributes, resource)
+            mappings = nested_model_mappings(attributes)
+
+            nested_resource = fetch_or_build_nested_resource_for(resource, index, attributes)
+
+            mappings.fields.each do |field|
+              field.parse_input(attributes, nested_resource)
             end
 
             params[nested_attributes_key][index] = attributes
@@ -17,13 +23,29 @@ def parse_input(params, resource)
         end
       end
 
-      def nested_model_mappings
-        @nested_model_mappings ||= AttributeFieldMappings.new(reflection.klass)
+      def nested_model_mappings(nested_attributes)
+        model = nested_attributes[:type].try(:constantize) || reflection.klass
+        mappings = attributes_mappings_for(nested_attributes)
+
+        @nested_model_mappings ||= AttributeFieldMappings.new(model, mappings: mappings)
       end
 
       def nested_attributes_key
         @nested_attributes_key ||= :"#{ name }_attributes"
       end
+
+      def fetch_or_build_nested_resource_for(parent, index, attributes)
+        nested_resources = parent.association(name).load_target
+
+        if (id = attributes['id'].presence)
+          nested_resources.find { |res| res.id == id.to_i }
+        else
+          parent.association(name).build(attributes.slice('type')).tap do |resource|
+            attributes['id'] = "__#{ index }"
+            resource.define_singleton_method(:id) { attributes['id'] }
+          end
+        end
+      end
     end
   end
 end

lib/para/attribute_field/nested_one.rb

@@ -1,11 +1,15 @@
 module Para
   module AttributeField
     class NestedOneField < AttributeField::BelongsToField
+      include Para::AttributesMappingsHelper
+
       register :nested_one, self
 
       def parse_input(params, resource)
         if (nested_attributes = params[nested_attributes_key])
-          nested_model_mappings.fields.each do |field|
+          mappings = nested_model_mappings(nested_attributes)
+
+          mappings.fields.each do |field|
             field.parse_input(nested_attributes)
           end
 
@@ -15,8 +19,11 @@ def parse_input(params, resource)
         end
       end
 
-      def nested_model_mappings
-        @nested_model_mappings ||= AttributeFieldMappings.new(reflection.klass)
+      def nested_model_mappings(nested_attributes)
+        model = nested_attributes[:type].try(:constantize) || reflection.klass
+        mappings = attributes_mappings_for(nested_attributes)
+
+        @nested_model_mappings ||= AttributeFieldMappings.new(model, mappings: mappings)
       end
 
       def nested_attributes_key

lib/para/attribute_field/relation.rb

@@ -25,8 +25,12 @@ def through_relation_source_foreign_key
         @through_relation_source_foreign_key ||= reflection.source_reflection.foreign_key
       end
 
+      def polymorphic_through_reflection?
+        !!(through_relation && reflection.source_reflection.options[:polymorphic])
+      end
+
       private
-      
+
       def resource_name(resource)
         Para.config.resource_name_methods.each do |method|
           return resource.send(method) if resource.respond_to?(method)

lib/para/attribute_field_mappings.rb

@@ -2,11 +2,12 @@ module Para
   class AttributeFieldMappings
     UNEDITABLE_ATTRIBUTES = %w(id component_id created_at updated_at type)
 
-    attr_reader :model, :fields_hash, :whitelist_attributes
+    attr_reader :model, :fields_hash, :whitelist_attributes, :mappings
 
-    def initialize(model, whitelist_attributes: nil)
+    def initialize(model, whitelist_attributes: nil, mappings: nil)
       @model = model
       @whitelist_attributes = whitelist_attributes
+      @mappings = mappings || {}
 
       process_fields!
     end
@@ -52,7 +53,7 @@ def process_fields!
         end
       end.with_indifferent_access
 
-      Para::ModelFieldParsers.parse!(model, fields_hash)
+      Para::ModelFieldParsers.parse!(model, fields_hash, mappings)
     end
 
     def build_field_for(attribute_name, type)